Embryology Flashcards
What does the first pharyngeal arch gives rise to?
The maxillary prominence and mandibular prominence (Meckel’s cartilage)
The first pharyngeal is associated with what nerve?
The trigeminal nerve
Gives rise to muscles of mastication (muscles to rember are tensor vali palatini and tensor tympani)
What pharyngeal arch does the common carotid artery comes from?
Third
Which pharyngeal arch gives rise to only the lower body and horn of hyoid bone?
Third
The pharyngeal pouches come from what layer ?
Endodermal|inner surface
What structure develops primarily into the thyroid gland?
Foramen cecum at the base of the tongue —— for a short time the gland is connected to the tongue via the thyroglossal duct
In a patient born with complete first (pharyngeal) arch syndrome what structures will remain unaffected?
Stapes
This syndrome occurs because the third and fourth pouches fail to differentiate between the thymus and parathyroid glands which results in the baby being born without a thymus and parathyroid glands——Congenital hypoparathyroidism
Digeorge syndrome
Remnants of a cyst occurs in the tongue or anterior part of the neck, usually inferior to hyoid bone.
Most cysts are observed at the age of .
Most a asymptomatic and movable and contains thyroid tissue.
Perforation of the skin may occur which opens in the median plane of the neck and anterior to laryngeal cartilages.
Name thus congenital anomaly ?
Thyroglossal duct cyst and sinus (perforation of skin)
Clinical significance of ectopic sites of thyroid glands
Incomplete movement of thyroid gland results in a sublingual thyroid gland that appears high at the neck just inferior to hyoid bone —- usually only thyroid tissue present
What are the components of the pharyngeal arches ?
Mesenchymal core —from mesoderm
Ectoderm
Endoderm
Truncus arteriosus
Cartilaginous rod forms skeletal arch
Muscular component
Sensory and motor nerves
First pharyngeal pouch forms what?
The tympanic membrane and pharyngotympanic tube
Second pharyngeal pouch forms what?
Forms the tonsils crypts
Third pharyngeal pouch forms what?
Inferior parathyroid gland and thymus
Fourth pharyngeal pouch forms
The superior thyroid gland
What is Treacher Collin’s syndrome?
An autosomal dominant disorder characterized by the malar hypolplasia (underdevelopment of zygomatic bones of the face). A first pharyngeal arch syndrome. ——insufficient migration of neural cyst cells
What is Pierre Robin syndrome?
A first pharyngeal arch syndrome which is associated with hypoplasia of the mandibular,e, cleft plate, and defects in eyes and ears. Bilateral cleft plate and posterior displacement of the tongue.
Match pharyngeal arches with the muscles and cranial nerves they’re grouped with.
First Second Third Fourth Fifth
First : trigeminal nerve Second : Facial nerve Third: Glossopharyngeal nerve Fourth: superior Laryngeal branch of vagus nerve Fifth: Recurrent Laryngeal nerve
Fourth and six arches forms what cartilages ?
Thyroid and cricoid cartilages
Second pharyngeal arch forms what ligaments and bones?
The stapes bone and the stylohyoid ligament and lesser horn of the hyoid bone
First pharyngeal arch forms what bones?
Malleus and Incus
First pharyngeal arch forms what muscles ?
Muscles of mastication
The second pharyngeal arch forms hat muscles ?
The stapedius, stylohyoid,posterior belly of digastric, auricular, muscles of facial expression
The third pharyngeal arch forms what muscles ?
Stylopharyngeus muscle
